114 NUDIBRANCHIATA.—TRITONIAD&. 
“These creatures have a peculiar manner of 
throwing the head towards the tail, and flouncing 
the tail towards the head, when they are desirous 
of removing any object of annoyance ; it 1s at that 
time these animals seem to recover from their tor- 
pidity, and evince the greatest activity in their 
movements. When much annoyed, they throw 
the body about with great activity, coiling up the 
head, tail, fins, &c. in a somewhat rotundiform 
position, and if the tormenting object is not re- 
moved, dash out again in full activity of body, 
then return to the rotundiform position, and there 
remain for a short period, apparently exhausted 
by their efforts; but on the cessation of the iri- 
tating cause, the animal quietly resumed its original 
position, perhaps dropping one or two of its wearied 
fins, according as its own sensations of ease or 
comfort might dictate. 
‘When nothing irritated this tender Mollusk, it 
would remain tranquilly floating upon the surface 
of the water, with scarcely any movement but that 
which proceeded from the undulating motions of 
the digitated extremities of the fins, as well as 
an occasional slight twisting action of the same 
organs. 
‘““T placed some small specimens of Porpita in 
the glass of water containing the Glauci, to observe 
if they would attack them. or some time one of 
the Glauci was close to a Porpita, and was even 
annoyed by the tentacles of the latter touching its 
back ; yet the Glaucus bore this, although with the 
usual characters of impatience, yet without at- 
tempting to attack it. At last it seized the Por- 
pita between its jaws, and by aid of a powerful 
lens, an excellent opportunity was afforded me of 
